Android Spinner List Example

A Spinner in Android is a dropdown menu that allows users to select one item from a list. Here, we'll create a simple Android app using Java that includes a Spinner and displays the selected item.

Step-by-Step Guide

1. Set Up Your Project

Open Android Studio and create a new project. Name it SpinnerExample and select Empty Activity.

2. Update the Layout File

Open activity_main.xml and add the Spinner element:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <Spinner
        android:id="@+id/spinner"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"/>

    <TextView
        android:id="@+id/selected_item"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@id/spinner"
        android:layout_centerHorizontal="true"
        android:layout_marginTop="20dp"
        android:textSize="18sp"/>

</RelativeLayout>

3. Update the MainActivity

Open MainActivity.java and update it to initialize the Spinner:

package com.example.spinnerexample;

import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Spinner;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

    private Spinner spinner;
    private TextView selectedItem;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        spinner = findViewById(R.id.spinner);
        selectedItem = findViewById(R.id.selected_item);

        // Array of items for the spinner
        String[] items = {"Apple", "Banana", "Cherry", "Date", "Elderberry"};

        // Create an ArrayAdapter using the string array and a default spinner layout
        ArrayAdapter<String> adapter = new ArrayAdapter<>(this, android.R.layout.simple_spinner_item, items);

        // Specify the layout to use when the list of choices appears
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);

        // Apply the adapter to the spinner
        spinner.setAdapter(adapter);

        // Set the spinner item selection listener
        spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
                // Display the selected item in the TextView
                String item = parent.getItemAtPosition(position).toString();
                selectedItem.setText("Selected: " + item);
            }

            @Override
            public void onNothingSelected(AdapterView<?> parent) {
                // Another interface callback
            }
        });
    }
}

Explanation

1. Layout File (activity_main.xml)

In the layout file, we added a Spinner and a TextView. The Spinner allows users to select an item, and the TextView displays the selected item.

2. MainActivity

In the MainActivity, we perform the following steps:

• Initialize the Spinner and TextView using findViewById().
• Create an array of items to display in the Spinner.
• Create an ArrayAdapter to hold the items and set it to the Spinner.
• Set an OnItemSelectedListener on the Spinner to handle item selections and display the selected item in the TextView.

Conclusion

By following these steps, you can easily create a Spinner in an Android app using Java. This example covers the basics of setting up a Spinner and handling item selections.